Polarization patterning in ferroelectric nematic liquids via flexoelectric coupling

The recently discovered ferroelectric nematic liquids incorporate to the functional combination of fluidity, processability and anisotropic optical properties of nematic liquids, an astonishing range of physical properties derived from the phase polarity. Among them, the remarkably large values of second order optical susceptibility encourage to exploit these new materials for non-linear photonic applications. Here we show that photopatterning of the alignment layer can be used to structure polarization patterns. To do so, we take advantage of the flexoelectric effect and design splay structures that geometrically define the polarization direction. We demonstrate the creation of periodic polarization structures and the possibility of guiding polarization by embedding splay structures in uniform backgrounds. The demonstrated capabilities of polarization patterning, open a promising new route for the design of ferroelectric nematic based photonic structures and their exploitation. Ferroelectric Nematic Liquid Crystals (FNLCs) have potential in applications due to their unique combination of fluidity, spontaneous polarization, large dielectric permittivity, and second-order non-linear optical properties. Sebastian et al. show the patterning of electric polarization in FNLCs by photoalignment which exploit flexoelectric coupling between polarization and splay director deformations.